Mild hydrogenation of catalytic reformate



July 26, 1960 l.. D. RAMPINO ETAL 2,946,742

MILD HYDROGENATION oF C ATALYTIC REFORMATE 3 Sheets-Sheet 1 Filed Jan.2. 1958 July 26, 1960 L. D. RAMPINO ET -AL Filed Jan. 2. 1958 5Sheets-Sheet 3 GLASS MANIFOLD DEPOSIT RATING.

MG. /LITER. 2O

'5 45o 50o soo 70o REACTOR TEMPERATURE.

GLASS MANIFOLD DEPOSIT RATINGl 'vla/LITER. 20

I5 I I I I I I I l I o 2O 4o 6o eo Ioov.

PERCENT BROMINE NUMBER REDUCTION.

-z\`\\ 50 6o L5 -7O BR INE NUMBER PERCENT BROMINE PLOTTED As ,o UMBERRECIPROCAL). 8O REDUCTION 0.5 FIG' 5 90 INVENTORs 604530 2o I5 Io LIQUIDHOURLY SPACE VELOCITY (PLOT'TED AS RECIPROCAL) BY 2,946,742 PatentedJuly 26, 1960 Calif., assignors toTidewater Oil Company, a corporationof Delaware s f Filed Jan. 2, 1958, Ser. No. 706,682

11 Claims. (Cl. 208-143) l This invention relates totheV catalyticreforming of naphtha fractions to produce gasoline constituents of highantiknock quality. More particularly, it relates to a combination ofcatalytic reforming with a novel process for obtaining gasoline withgreatly improved storagestability and less tendency to formV gums ascompared with previous high-octane catalytically reformed gasolines.

Progress in the automotive industry has resulted inthe development ofgasoline engines of higher and higher compression ratios requiringgasoline fuels of correspondingly higher antiknock properties or octanerating. To meet this demand, the petroleum industry has developedvarious processes for producing gasoline of increased octane rating. Oneof the more eicient of such processes (and the one concerned in thepresent invention) is known as catalytic reforming, wherein low-octanenaphtha is contacted under pressure in the vapor phase with a suitablecatalyst at temperatures above 800 F. in the presence of substantialvolumes ofk hydrogen. A common type of catalyst used for catalyticreforming is platinum supported on a suitable carrier such as speciallyprepared alumina containing chloride or fluoride .or both or speciallyprepared silica-alumina. platinum catalysts are marketed which willproduce 85 to 90 clear research octane number (ASTM Method D 908-53)reformate under operating conditions sufficiently mild that the catalystcan be used for extended periods of time without regeneration to removecarbon formed by undesirable reactions. ,t

More recentdevelopments in the automobile industry have created a needfor gasoline having a research octane number substantially above 90(before the addition-of tetraethyllead or other anitknock compound) andpreferably above 96. To meet this requirement by catalytic reformingprocesses now in use, it has been necessary to increase the severity ofoperating conditions to an extent that a substantial amount ofhydrocracking and polymerization occurs. lUnder these severe conditionsa considerable portion boiling above about 400 F. is usually produced;this portion is almost entirely aromatic and therefore has a very highoctane number. However, this portion generally contains substantialamounts of dicyclic aromatics such as naphthalene, the two methylnaphthalenes, and the several dimethyl naphthalenes. The

presence of these dicyclic aromatics in gasoline, even in lowpercentages (such as 1% or even less) has been considered heretofore tobe deleterious and has been regarded as the cause of varnishes, gums,and lacquers in engines using such fuel.

Previously, it has been proposed to removcthese-Supl Several lsuchposedly deleterious materials by rerunning the severe reformateso as tocut out the heavy bottoms. This, however, requires additional equipment,a Asubstantial capital expenditure, and the continuing expense ofheating the material.. Moreover, the advantages of rerunning arelillusory. When fresh, the rerun stock has less tendency to form gumsthan fresh reformate which has not been rerun. However, after it hasaged a few Weeks, the rerun stock has been found to have a greatertendency to form gum than similarly aged reformate that was not rerun.

We have found that superior results can be obtained by subjecting thesevere reformate to a very mild hydrogenation. It is interesting andunexpected to nd that the mildhydrogenation results in induction systemratings approximately equalwto or better than those of the fresh rerunmaterial from which the supposedly dele-` terious materials wereeliminated. Of equal interest andsurprise is the fact that our mildlyhydrogenated re.v formate containing the -bottoms has a storagestability superior yto both theoriginal reformate and the rerunreformate and a somewhat lower octane loss than the rerun material. Allthis is quite surprising in View of the fact that analysis appears-toindicate that the supposedly deleterious dicyclic aromatics are stillpresent in substantially the same quantity asbefore. Whether the mildhydrogenation removes or reconstitutes some agent` that reacted withthese dicyclic aromatics to form gums or jwhether the mild hydrogenationrenders innocuous some completely different gum-forming constituengwe donot know at present, but the results are impressive. Moreover,v theprocess of this invention is substantially less expensive than rerunningand requires much less capital investment. Also, there is no loss inproduct volume after hydrogenating, as'there is where the bottoms areremoved.

A fact worth remarking is 'thatheretofore hydrogenation of reformate wasdisfavored, because (l) the dicyclic aromatics presumed to be the causeof the gum were not considered to be changeable by hydrogenation atpressures lower than about 1000 p.s.i., and ,(2) hydrogenation wasconsidered certain to reduce the octane number by saturating theremaining oleins into lower-octane parafiins. However, we have foundthat mild hydrogenation under the right conditions substantiallyeliminates the gum-forming constituents and improves the storagestability of the gasoline but gives only a negligible lowering, if any,in octane number. )The exact conditions under which hydrogen-ationshould be carried out may vary under circumstances which are explainedrin the course of this speciiication. However, in general it may be saidthat the mild hydrogenation may be (and, for economic reasons,preferably is) carried out at substantially the same pressure Kas thatused in the' reforming operation, and that excellent results may beobtained by hydrogenating at temperatures in the neigh- V borhood of 500to 600 F., with a space velocity (LHSV) of approximately 30, andhydrogen consumption of around 20 to 30 s.c.f./bbl. or less. Temperatureas low as about 450 F. may be used with somewhat less desirable results.Commercial cobalt molybdate is the presently preferred catalyst. Undersuch circumstanc the octane number loss may 'be kept down to as low as0.1 ,or even lower, for example, while the gum-forming tendencies arereduced by veryjsignicant margins.;

The etfect of mild hydrogenation in the present invention is especiallysurprising in view of vthe fact that 'it is conventional to precede thestep of catalytic reforming with a step of severe hydrogenation for thepurpose of prolonging the life of the reforming catalyst by removal ofarsenic, sulfur, nitrogen, and other poisons for the catalyst, all ofwhich can be removed by rather severe hydrogenation prior to catalyticreforming. But the present invention is not lconcerned withhydrodesulphurization or the removal `of other catalyst poisons. Infact, the charge that is catalytically reformed prior to the novel ,mildhydrogenation -step of our invention will usuallyhave no arsenic andnegligible sulphur vandnitrogen content, and even if this `were not thecase, the product emerging from the catalytic Yreformer would still havea sulphur content substantially less than j:'oo of 1% and even lessarsenic and nitrogen.

We also recognize that it is old to -hydrogenate catalytically crackednaphtha, 4where the bromine numbers before hydrogenation are many Ytimesgreater vthan in catalytically reformed naphtha fractions. For example,the catalytically reformed naphtha used in our linvention normally has abromine numberin the order of about 4, Whereas, the bromine numbers ofcatalytically cracked naphthas are rarely less than 20 or` 30 and may beYmore than 100. In fact, catalytically cracked naphtha often 'has abromine number as high as 140. Hydrogenation of such material Yispracticed, as 'in the aforementioned step prior to catalytic reforming,to -reducethe sulphur content, which may be very high, in the order of0.3% to 0.5%, many times as great asin the material of the presentinvention, which has been desulphurized Vand subjected to catalyticreformation (as distinct from catalytic cracking) and therefore has aquite low bromine -number and practically no sulphur content. Normallyit might be thoughtv that hydrogenation of such a fraction would beuseless since there is no sulphur to take out and since the remainingolens in -the naphtha are desirable constituents whose hydrogenationwo'uld substantially lower the octane number of the lfuel.

While we are not aware of the exact chemical mechanism of our process,the quality of our improved fuel speaks for itself. Moreover, it appearsto be b eneicial to use our process even when the bottoms materials havealready been removed by fractionation or when they are to be laterremoved by fractionation subsequently to the mild dehydrogenation stepwhich our invention proposes.

' Other objects and advantages of the invention will appear from thefollowing description of preferred embodiments thereof.

In vthe drawings:

Fig. 1 is a flow diagram of a portion of a typical catalytic reformingprocess, -preceded by hydrodesulfurization and subsequentlyincorporating a process embodying the principles of this invention.

Fig. 2 is a simplified diagram of a modified process also embodying theprinciples of this invention, wherein the hydrogen is separated from thereformate and hydro'- gen is added again at the step of hydrogenation.

Fig. 3 is a graph plotting the glass manifold deposit rating ofhydrogenated reformate against the reactor temperature of thehydrogenation unit.

Fig. 4 is a graph plotting the glass manifold deposit rating ofhydrogenated reformate against the percent reduction of the brominenumber by hydrogenation.

Fig. 5 is a graph plotting the reciprocal of ,the percent reduction ofthe bromine number against the reciprocal of the liquid hourly spacevelocity.

In the illustrative example shown in Fig. '1, the naphtha fed to thecatalytic reformer is hydro'desulphurized prior thereto. By way ofexample only, fresh feed 1 is shown sent along with hydrogen from line 2through a preheater 3, to raise the temperature of the feed 4preheaterto a suitable level and then the preheated stock Ain line 4 is fed to ahydrogenation unit 5. For a unit 5 using -cohalt-molyhderra-aluminacatalyst, lthe reactor 5 -`will be at a temperature of about 750 F. to850 F. and at a pressure of about 500-1000 p.s.i.g. Hydrogenation in theunit 5 reduces the sulphur content of the feed to a negligible amountand also saturates unsaturated hydrocarbons.

The hydrodesulphurized stock in line 6 may then be cooled by a heatexchanger '7 and sent to a high-pressure liash separator 8 where richgas is flashed olf in line 9 as feed to an absorber tower 10.Co'ndensate in line 11 goes from the high-pressure separator 8 to alow-pressure separator i12 where it is combined with rich oil in line 13from the absorber tower 10. Hydrogen from the absorber '10 V'may Yberecycled 'through lines 14 and 2, hydrogen -makeup being added throughline 15. y Y t Ihe ,condensate :in Vline .ltvtis .fed .from the.,lowapressure separator 12 to a fractionation tower 1.57, vivvhile thegas taken from the separator 12 at line 18 may be sent to gas recovery.Gas vfor recovery is similarly drawn olf by line ,19 Afromthefractionator 17. Bottoms may be withdrawn from the fractionator 17through line 20; light fractions may be drawn olf through line 21 andheavyifractions through line 22. 4

'Naphtha charge forzthe catalytic reformer passes from the fractionator17 via line 25, a pump 26, and a heat exchanger 27, to a preheaterv28,*Where the temperature isgraised more than 800 F., almost alwaysmore `than 900 F., and'usually about 950 'F. at 500 psig. 'Hydrogen fromline 29'is preferably 'added be'fore'preheating, land-the mixture ofnaphtha and hydrogen Vis then fed to a first reactor 30 through line 31.(The hydrodesulphurization step, indicated by numerals 3a-23, may beomitted where the sulphur and nitrogen ycontent of the vnaphtha 1 Iislow and where the naphtha 1 is substantially arsenic free or where thereexist suitable means for regenerating `,the reforming catalyst. V'lnthis event the naphtha 1 and 25 would be identical.)

'Platinum supported on alumina or silica may be vthe catalyst inthereactor 30. Normally there is more than one reactor, with substantiallyidentical conditions therein; by way of example, we show herein threereactors, vthe partially reformed material from the rst reactor '30being fed Vthrough line 32 to a reheater 33 (to raise the temperatureIagain vafter it has dropped in the endothermic reaction in the reactor30) and thence via line 34 to' a second reactor 35. From the secondreactor 35 the material is returned by line 36 to theren heater 33 (ortoa separate reheater) and Icharged by line 37 to a third reactor 38.

All these preceding steps are normal practice. But the normal procedurefrom here -onis to `feed the reformate from the third reactor 38 to aseparator 40, whence hydrogen is recycled via lines 41 and 29. Theconden sate fro'm the separator 40 is fed through line 42 to astabilizer 43, whence gas is taken off through line 44 and stabilizedreformate is sent through line 45 Yto storage or blending.

In the present invention, however, we feed the vreformate coming fromthe iinal reactor 38 through line 48 and a heat exchanger 49 to ahydrogenation reactor 50, wherein very mild conditions obtain.Preferably the reformate so passed still contains its excess hydrogen;in other words, preferably the mild hydrogenation 50 precedes theseparator 40. Preferably, the heat exchanger 49 reduces the'temperatureof the reformate to about 500-600 F. prior to hydrogenation, a secondheat exchanger 51 in line 52 after the hydrogenator 50 being used toprepare the refonnate for the separator 4e. Either heat exchanger 49 orSi or both may be the other side of the heat exchanger 27 or some otherheat exchanger in the system, in order to use vthe heating and coolingsteps with maximum eiiiciency, for example, in

the manner 0f the heat exchanger S3 where the stabilized V74 forintroduction to the hydrogenator 75.- v

agrava reformate in line 45 heats the cooled condensategin line In thepreferred process illustrated in Fig. 1 certain things should be notedparticularly: (1) there is no separation of hydrogen from the reformatebefore hydrogenation; the hydrogen excess resulting from reformation isused (but only partially and infact in ysmall percentages of thehydrogen present) in the mildA hydrogenation step; (2) the pressure(normally about 500 p.s.i.g.) used in Ythe reforming reactors ispreferably maintained through thehydrogenation step, so that no pressurereduction regulator or compressor need be added to the system in orderto carry out the present invention; (3) the only bed 50, a relativelyinexpensive installation;` and (4) as stated earlier, the heat given upinjthejheatfexhangers 49` and 51 is preferably utilized elsewhereinthissame system, e.g., in the heat exchanger 27,; fjf'v1jfjQQfM "jj fThe general process now being understood in `i srelation to conventionalYcatalytic reforming, lit will eV pointedv out that normally the naphthafed to the reformer has already been hydrogenated, usually severely, toremove the sulphur, nitrogen, and-arsenic and that. any

Vequipment really added is the ycobalt-molybdate catalyst sulphur,nitrogen, or arsenictremaining is removed by the platinum in one of thethree reactors 30, 35, and 38. Even if the naphtha is not hydrogenatedbefore reformatiomthere is still no sulphur or arsenic in the feed tothe hydrogenator 50, yet the process isinall events useful in enhancingthe storage life of the reformate, in preventing later development of4gum-forming constituents, and in obtaining cleaner engineperformance-all this -without any substantialreduction of the researchoctane numberl and whether -or notv the bottoms are removed from thereformate prior to or subsequent to the mild hydrogenation step of thisinvention. Modifications are` shown inFig. 2, where the diagram isIgreatly simplified. Naphtha, .Whether previously hydrodesulphurized ornot, Yis fed throughlinertl, pump 61, andheat exchanger 62, mixed withhydrogenv from line k63:,.heated tothe desired level inheater, 64, andtreated in a catalytic reformer 65,k here shown condensed into oneblock, though the block may represent oneor several units. Then thereformate in line 66 isfed .to a separator 67 where the hydrogenisremoved through line68. j i, t j;

The condensate from the separator 67 may be fed through valve 70, line71, heat exchanger 72, valve73, and line74 into a hydrogenation reactor75,operated under the conditions described under Fig. ,1, exceptfthatlhydrogen is fed thereto via line- 76, valve 77,1 a'nd'heat exchanger 78in the desired ratio, either from/line 68jor from a separate source ofhydrogen via line 79.'A

After hydrogenation as before, the mildly hydrogenated reformate may befed'via separator 80, line 81, heat exchanger S2, and line 84 into astabilizer 85, asiin Fig. 1, Where the gas is taken off via line 86 andstabilized reformate via line 87 and heat exchanger 88.V f

As also shown in Fig. 2, the reformate may befractionated either beforeor after hydrogenation or both, in

korder to meet end-point specifications of certain consum- 95,` bottomsvia line 96, and the remainder 'returned by heat exchanger 97 and line9S to the valve 73 Yand Yline Alternatively,A or in addition if desired,the mildly hy drogenatedreformate produced by this'invention may be sentvia valve 83l and line l-100 intov a fractionator -101-,

whence gas is remved'by line 102, bottoms by line 103. T he remaindermay then be sent via line 104, valve 105, Y

line 81, and heat exchanger 82, into line 874 and the stabilizer 85. Afurther alternative is fractionation after stabilization. The stabilizedreformate may be sent from line 87 via valve 110 and line 111 intofractionator 112 -:from whichthe bottoms may be removed through line113. The overhead may be taken out through line 114 and returned to theline 87 through'valve 115. Any or -allof thesefractionationsteps mayalso be used in the process of Pig. l, ifd'esired. Y e ,A Y VExperiments made in accordance with' the processes of Figs. l and 2 showfurther interesting features ofthe invention. Two different reformateswere used in these experiments, made under similar'conditio'ns'butatdifferent times. For purposes of this discussion, they arerref ferred toas Reformate Aand ReformatejB. In both instances, a platinum reformingcatalyst was used.

Pertinent data is shoWnir Table I. y

TABLE 1 v Y n v Data on'reformaze* i9 OperatingOondltions of ReformingRefomato lielogmate Temperatura:r Hf m (Max.) 974 980 910 916 940 947500 500 2 2 6,500 6, U00 'Yield-(Vol.'percent 85.5 r83.5

. Retormate l Analysis Charge Brmme'No.L..-.' 0.19 a s 4.5

1 V I Suriname 9()v Percent Sulfur v 0.01v l. `Basic Nitrogen.. NlL

ASTM Gum l0. 8V @7.8 Octane Number v t,

`F1 Clear H94.3v 94,6 vl-1+3.0 cc.TET1 V100.0 A. Dlsttllatlon' 'entlyrequired higher temperatures to attain the same oo,-

ADue to aging of reforming catalyst, Reformate B appartane as ReformateA with more hydrocraclking and lower yield. 4 Yf Mild hydrogenation wascarried out separately on Re'- formatesfA and B using c obalt molybdatein the form of f' pellets. The fresh catalyst maybe preconditioned,if'desired, by desulfurizing a small amount of stock conta'ining'sulfurcompounds, in this case, heavy catalytically cracked naphtha. A pressureof 500 p.s.i. was used throughout, the temperature and the liquid hourlyspace velocity being varied. v v

Hydrogenfconsumption was measured to be about 20-30 s.c.f./bbl includingsolution losses. Since solution losses are probably about 20s.c.f./bbl., the chemical consumption appears to be under or about v10s.c.f./bbl. The mole ratio of hydrogen to hydrocarbon was 6 to 1, vthenormalA ratio for reformer efliuent.r L

The data obtained from hydrogenation runs 'of: Re-` formates Av and B,respectively, are shown in Tables Il andIII." 'Y V TABLE II 50% mildlyhydrogenated Vreforrnate.a11d 50% light-Sata i lytically crackedgasoline (Table VI) was used to s111111- Y Data obmmed hydmgemtw" "ms ofReformae A late commercial gasoline `and givemore Ytypical vaporizationin the glass manifold apparatus. Operating Octane No. Conditions .RunNo.BrgNo. TM TABLE y 11m 'r LHsv 1 fence gni?? cem Glassmamfold deposits 1of Reformatie B v.Hydrog'enrrted at various temperatures `and spacevelocities Charge (Re- 10 tomate AL "5' Reactor Glass 1-v ggg g5 0:694:1 '9919 'Reduenon1nBnNo. Bromine Temp., LHSV .Malfld 500 `1 v0 93.099.9 No. F. "Deposits, eno 1o 5.8 93.8. 199.9 1 me-v/1iter 700 4 lg.93.7 99.7 y 33 ig 1520 15 85% 0.7 70o 15 122g: 425 5 o. 2 69% 1 4 k500`15 17.16 425 o. 2 '11T 1l 3 450 10 2am: 45o 5 1. e 55T 2.0l 70o :so18:3; 450 15 1 g 530 2.1 60o 4`45 17. 7 500 5 o. s 6o'7 1. s ytou- 3o:`17:2 500 .1o 2. 6 62'7 1. 7 .450 20 L21. 3 500 1o 0.8 20 44 Y 2.5 50d45 Y21.4 500 15 1. 4 Raw Reiormate `4.--5y i ,30,8 60o g gg y ggg 5 4:0l Test :Method: Evaluating .Gasolines for Induction System SGums 700 5 28 O. C. Moore,jJ. L. Keller, W. L. Kent, F..,S. LiggetLUnion OllCoxnpny700 15 3, 4 of California, presented atSAENational Fuels and LubricantsMeeting, 700 1. s Tulsa, Oklahoma, November-445, 1954.

The lowest vglass manifold deposit "ratingvlrl/.RS obtained TABLE i111with reformate hydrogenated at l500 F; to A6 0 SZ; V bromiue numberreduction. i Data obtained on hydrogenatz'on -runs of Reformatie B 30 BLv1 Operating 'I rdutction vRnnNo. Conditions BrzrNo. ASTM Dnslii;Properties of vlight catalytcally cracked gasoline used in Gum (Blended)blend o ind ction s stem d o t TSmp.. Lnsv man. if r u. y el s e F'Distillation, F.:

ji[.B.P. 98 Char e Reormie 1(3) s 5 7. s so. s 10 .125 22- 70o v115 0.79. 4 22. 7 50 160 23- 500 15 1.4 1.2 17.6 90 24. o 1o 1.3 a2 23.6 40 232at it is at E-P- 292 2s--- Y at s it si istie i 140 28"., 29 Y suo V452-5 se 21.4 Peroxidulglo Sulfur v .10 45 Nitrogen V.' .005

YAseshown in Table lV,'the more complete. the., hydrogenation, asmeasured by loss inj-bromine number, the Vgreater the lossin octanenumber.

`I'T1tratlon using KBr-KBrOa-solutlon. Rei.: Frances, Ind.'andEng.18,"p.'821 (1926); Lewis and Bradstreet, ibld.,-'Anal. Ed. 12, 387 1Thus, to minimize octane loss it is desirable to ,use as,mldhydrogenation conditions as will ygive adequate improvementinproduct quality.

.As .shown Ain Table lli, a series of runs .on Reformate AAwere madeattemperatures of 450, 500, 600, .and 700 F. and at four .levels ofhydrogenation. The level of hydrogenation was controlled by varying thespace `-velocity.

Glass manifold deposits obtained with .blends of .this material areshown in Table V. The blend containing Plotting lglass manifold :depositrating l-vs. Areactor temperature at this level of hydrogenation1(5560%bromine lnumber reduction) gives a low at 500 `F. (See Fig. 3;)

Plotting .glass manifold deposit ratingvvs. percentibromine numberreduction-at 500 F. rreactor temperature gives a low at about 60%reduction (see Fig. 4).

The bromine number reduction appeared to follow a second order reactionrate. An approximate straightflineVV was obtained by plotting thereciprocal of Athe Ybromine number 4against the residence time or thereciprocal of the space velocity, as lshown in Fig. 5. l.From this, thetemperature and space velocity necessary'forfagiven conversioncan'beapproximated quite readily.

From the foregoing :data and drawings, the optimum condition'sappear tobe:

Percent reduction inbromiueISIo.Y 60.

Space velocityLHSV v .i-....- 30 approx. Hydrogen consumption,s.c.'f./;bb1. .20-30 or less.

Octane numberloss under optimum conditions isabout 0.1 RON.

The ASTM gum (ASTM Method D SSI-54T) onhigh severity untreated reformateis relativelyhigh. Valuesof 7.-810.8 .were obtained Yon `the lreformateused in these experiments. A summary ofASrTM gum data is Ipresented in.Table VI. Lowest gums were. obtained inthe -range from-.425 10.500,-F.r reactor. temperature.v

TABLE vn" ASTM gum content at various reactor temperatures No. of ASTMReactor Temp., F. Runs High Gum Average Low Y Comparison betweenhydrogenated reformate and redistilled reformate with respect to octanenumber loss, and induction system deposits (on fresh samples) andperoxide formation on storage is made in Table VII.

These data show .that hydrogenation of reformate leads to considerablyreduced induction system deposits. Freshly redistilled reformate showsapproximately the same reduction in deposits; however, hydrogenatedreformate is much more resistant to peroxide formation on storage thanredistilled reformate. For this reason, hydrogenation is shown to be asuperior method of reducing the gum-forming tendency of reformates.

Table IX compares the glass manifold deposits obtained on redistilledand hydrogenated reformates Vafter aging for 1 month `at 110 F. usingair. Deposit data were obtained on blends containing 50% of reformateand 50% of the same light catalytic gasoline.

Also, as Table IX shows, the tendency for redistilled reformate to formdeposits on storage can be reduced if reformate is hydrogenated eitherbefore or after distillation.

TABLE IX Glass manifold deposits from aged reformates Glass manifolddeposits, mg.per liter Aged, full-range reformate |50% light catalyticgasoline Aged, 97% overhead reformate +50% light catalytic gasolineAged, mildly hydrogenated reformate +50% light catalytic gasoline 22.497% overhead reformate, mildly hydrogenated afterredistillationv andaged +50% light catalytic gasoline 20.4 Mildly hydrogenated reformate,distilled to 97% overhead after hydrogenation and aged |50% lightcatalytic gasoline 18.6

To those skilled in the art to 'which this invention relates, manychanges in construction and widely differing embodiments andapplications of the invention will suggest vthemselves without departingfrom the spirit and scope of the invention. The disclosures and thedescription herein are purely illustrative and are not intended in anysense to be limiting.

aback-1a o.

1.jA method forimproving the stora'gestabilit'y and induction-systemcleanliness of a. substantially non-ole- Ainicvnaphtha reformate thathas been severely reformed in the presence of platinum catalyst andhydrogen at temperatures above 9,00? F., withv the production ofadditional hydrogen and under conditions sucient to maintainthe brominenumber of -thev reformate below about 4.5, said method comprisingmildlyjhydrogenating said reformate in the absence of added olens and inthe presence of a hydrogenation catalyst at a temperature between 450and 600 F., at substantially the same pressure as the catalyticreforming and at a liquid hourly space velocity of approximatelySO; saidhydrogenation being insuilicient to cause a significant reduction in theresearch octane rating of the reformate.

2. The method of claim l wherein the reduction in bromine number of thereformate during the hydrogenation is about 40% to 60%.

3. A method for improving the storage stability and? induction systemcleanliness of a substantially non-ole-` nic naphtha reformate that hasbeen severely reformed in the presence of platinum catalyst and hydrogenat temperatures above 900 F., with the production of additional hydrogenand under conditions sufficient to maintain the bromine number of thereformate below about 4.5, said method comprising passing a stream,consisting essentially of said refonnate and said additional hydrogen,over a bed of cobalt molybdate catalyst under conditions suicient toreduce the bromine number of said reformate by about 40% to 60%; saidconditions being insuicient to cause a substantial reduction in theresearch octane rating of said reformate.

4. The method of claim 3 wherein the temperature at the cobalt-molybdatecatalyst bed is between 450 and 650 F., the pressure is about 500p.s.i.a. and the liquid hourly space velocity is approximately 30.

5. A method for improving the storage stability and induction systemcleanliness of a substantially non-olefnic naphtha reformate that hasbeen hydrodesulphurized and then severely reformed in the presence ofplatinum catalyst and hydrogen at above 900 F. and about 500 p.s.i. a.,with the production of 'additional hydrogen, comprising passing saidreformate in the absence of addedolefins over a bed of cobalt molybdatecatalyst in the presence of hydrogen at a mole ratio of about 6 to l ofhydrogen to hydrocarbons, at about 500 F., 500 p.s.i.a., yand a-t aliquid hourly space velocity of approximately 30; said conditions beinginsuicient to cause a substantial reduction in the research octanerating of said reformate.

6. A method for improving the stability and cleanliness of gasolinecontaining thoroughly desulphurized substantially non-oleiuic catalyticreformate reformed in the presence of a platinum type catalyst, withoutsignificant impairment of its research octane rating, comprising mildlyhydrogenating, up to a 60% reduction in bromine number, the eiiiuentstream of reformate in the presence of cobalt molybdate catalyst and inthe absence of added olelns.

7. The method of claim 6 wherein the hydrogen is obtained by passing theeuent stream directly to the hydrogenation while it contains hydrogenresulting from the catalyticreformatio'n.

8. The method of claim 6 wherein hydrogen is added separately to theeffluent containing negligible amounts of hydrogen, at thehydrogenation'step.

9. The method of claim 6 wherein the reformer effluent is fractionatedprior to hydrogenation to removel bottoms and obtain a desired endpoint. v

l0. The method of claim 6 wherein the hydrogenator effluent isfractionated subsequent to hydrogenation, to remove bottoms and obtain adesired end point.

11. A method for improving the stabilityandleganliness o f gasolinecontaining catalytic reformateof negligible olen content, withoutsigniicant impagirlnent of Yits researchrootane rating, comprisingcooling 'the 1effluent stream of reformate from a catalytic reformer toabout 450600 F, `and passing it with its-contained hydrogen directlywithout added olens through a bed of cobalt molybdate catalyst at aliquid hourly space velocity of about. 30, to obtain a ,net hydrogenconsumption :at said bed of about 2 0-30 s.c.,f./ bbl.

References Citedrin'he ile of this patent UNITED. STATES PATENTS Burk eta1 Apr. '4, "1944 Munday et al. v.. Ian. 16, u1945 Cole Jan. 11, `19494Howes et al. Dec.V `1-2, 1950 Brandon Feb.. 20, ,1951 Haensel Apr. '3,A195,6

Morbeck et a1. s iMr.10, 1959

1. A METHOD FOR IMPROVING THE STORAGE STABILITY AND INDUCTION-SYSTEMCLEANLINESS OF A SUBSTANTIALLY NON-OLEFINIC NAPHTHA REFORMATE THAT HASBEEN SEVERELY REFORMED IN THE PRESENCE OF PLATINUM CATALYST AND HYDROGENAT TEMPERATURES ABOVE 900*F., WITH THE PRODUCTION OF ADDITIONAL HYDROGENAND UNDER CONDITIONS SUFFICIENT TO MAINTAIN THE BROMINE NUMBER OF THEREFORMATE BELOW ABOUT 4.5, SAID METHOD COMPRISING MILDLY HYDROGENATINGSAID REFORMATE IN THE ABSENCE OF ADDED OLEFINS AND IN THE PRESENCE OF AHYDROGENATION CATALYST AT A TEMPERATURE BETWEEN 450* AND 600*F., ATSUBSTANTIALLY THE SAME PRESSURE AS THE CATALYTIC REFORMING AND AT ALIQUID HOURLY SPACE VELOCITY OF APPROXIMATELY 30, SAID HYDROGENATIONBEING INSUFFICIENT TO CAUSE A SIGNIFICANT REDUCTION IN THE RESEARCHOCTANE RATING OF THE REFORMATE.